A hydraulic shock absorber installed between a sprung member and an unsprung member of a vehicle is always exposed to ambient air, and hence dust and mud may accumulate on a piston rod projecting from a cylinder of the shock absorber. The dust and mud adhered to the piston rod adversely affect the lubrication of a sliding part between the piston rod and the cylinder, and cause a seal member sealing the sliding part to deteriorate.
In this context, JPH10-213223A published by the Japan Patent Office in 1998, proposes a cylindrical dust boot using a bellows in order to cover the piston rod projecting from the cylinder.
In this prior art, an end of the dust boot is connected to the projecting end of the piston rod. Another end of the dust boot is connected to an intermediate portion of the cylinder. The length of the bellows is set larger than a projecting length of the piston rod when it is elongated to a maximum elongated position.
According to the above construction, the bellows elongates and contracts according to the elongation/contraction of the piston rod, and the piston rod projecting from the cylinder is always shielded by the bellows from the dust and mud.